Engine starter



1944- J. w. FITZ GERALD 22,356,984

ENGINE STARTER Filed June 19, 19 13 5/0/91? d/D Deceased By Mary C HZzGra/d Exzcufr/x Patented Aug. 29, 1944 ENGINE STARTER John W. Fitz Gerald, deceased, late of Milwaukee,

Wis., by Mary C. Fitz Gerald, executrix, Milwaukee, Wis., assignor to Briggs & Stratton Corporation, Milwauke Delaware e, Wis, a corporation of Application June 19, 1943, Serial No. 491,504

2 Claims.

This invention relates to engine starters of the type wherein a pinion is automatically propelled into mesh with a gear of an engine to be started and is automatically retracted upon starting of the engine, and is concerned primarily withengine starters of compact design such as that forming the subject matter of the Gottlieb et al. Reissue Patent No. Re. 22,005, granted January 13, 1942.

One of the chief difficulties experienced in the past with small compact engine starters of this type was the difficulty of providing satisfactory stop means for limiting propulsion of the pinion toward mesh with the engine gear.

Where space requirements are no problem it is customary to mount a stop collar on the drive shaft of the starter to define the operative meshing position of the pinion. This requires the drilling of a hole in the drive shaft for the reception of a set screw to anchor the stop collar on the shaft.

In instances where space is at a premium and the starter mechanism must be small and compact, however, the drilling of a set screw hole in the drive shaft seriously weakens the shaft and sometimes results in breakdown during operation of the starter.

It is therefore an object of this invention to provide an engine starter mechanism of compact design with improved stop means for limiting propulsion of the pinion to its operative position without weakening any of the mechanism of the starter drive.

With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, com bination and arrangement of parts substantially as hereinafter described, and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawing illustrates one complete example of the physical embodiment of the invention constructed in accordance with the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a longitudinal sectional view through an engine starter embodying the principles of this invention with the parts shown in the position they occupy in the inoperative pinion retracted condition;

Figure 2 is a view similar to Figure 1 showing the pinion fully meshed with the engine gear and about to transmit rotation thereto; and

I FigureB is a cross sectional view through Figure 2 on the plane of the line 3-3.

Referring now more particularly to the accompanying drawing, in which like numerals indicate like parts, the numeral 5 designates an engine ring gear, only a, portion of which is shown, with which a pinion 6 is adapted to be meshed to transmit rotation of a drive shaft 1 of a starting motor 8 thereto.

The pinioni as is customary is mounted on the drive shaft 1 for rotary and longitudinal movement with respect thereto. An actuator 9 loose on the drive. shaft hasexternal screw threads l0 threaded into a rearwardly extending internally threaded sleeve II on the pinion to provide for advancing the pinion to and retracting the same from its operative position meshing with the ring gear; it being apparent that with the parts in their positions as shown in Figure 1, relative rotation between the actuator and the pinion sleeve efiects longitudinal forward propulsion of the pinion toward the engine ring gear 5.

Rotation isimparted to the actuator 9 from the drive shaft 1 by means of a flexible coupling designated generally by the numeral l2 having both endwise and torsional resiliency. The flexible coupling [2' is similar to that of the hereinbefore mentioned Gottlieb et al. patent and includes a collar l3 fixed on the drive shaft by means of a set screw l3 a distance rearwardly of the actuator 9.

This collar has a flange or abutment l4 axially spaced from but facing a similar abutment 9' on the rear of the actuator, and a rubber ring or collar I 5 is confined between these abutments under a degree of compressive force by means of a shell-like housing l6 encircling the flanges. One end of the housing 16 is provided with an inturned flange I! to engage behind the flange M on the collar l I while the opposite open end of the housing I6 is provided with a lock ring [8 which engages behind the flange 9' of the actuator. Thus, endwise motion apart of the actuator and collar II is limited and the rubber collar I5 is held under compressive force between the abutments with its ends frictionally engaged therewith.

The frictional engagement between the ends of the rubber collar and the flanges l4 and 9" establishes a yielding torque transmitting connection between the collar l3 and the actuator 9, and as in the aforesaid Gottlieb et al. patent, the rubber collar 15 acts to cushion the shock on the pinion as it takes up the load of the engine present instance, however, the pinion sleeve has a flange 2| at its rear end adjacent to the coupling I2 provided with circumferentially spaced radial lugs 22 received in slots 23 formed in the adjacent end of the shell 20. A look ring 24 secures the lugs 22 between the lock ring and the bottoms of the slots 23 in the shell and serves to fixedly mount the shell on the pinion.

The outer shell 20 extends rearwardly over the flexible coupling l2 to enclose the same, and has an inturned flange 25 formed at its rearward extremity substantially in line with the flange I! of the innershell when the pinion is in its retracted position.

This inturned flange 25 constitutes an annular stop abutment which cooperates with a bead 26 on the exterior of "the forward extremity of the inner shell I6 upon forward propulsion of the pinion to define the operative meshing position of the pinion as shown in Figure 2.

Inasmuch as the inner and outer shells are preferably cylindrical in shape and carry the cooperating pinion stops it will be seen that the starter mechanism and particularly the pinion sleeve and the pinion may be made as compact a possible.

From the foregoing description taken in connection with the accompanying drawing, it will be readily apparent to those skilled in the art that this invention provides an engine starter havin novel means for defining the operative position of the pinion and by reason of which the starter may be made exceptionally compact without weakening any of the starter mechanism.

What is claimed as the invention is:

1. An engine starter of the character described comprising: a pinion member movable to and from an operative position and including an internally threaded sleeve; an externally threaded rotatable actuator for the pinion threaded into said pinion sleeve; a member adapted to be secured to a drive shaft; a resilient driving connection between said member and the pinion actuator whereby rotation of the actuator through said driving connection relative to the pinion member propels the pinion member toward its operative position, said driving connection including a shell-like housing connected with the actuator and said member; a shell carried by the pinion sleeve and telescoped over said shell-like housing; and cooperating stop abutments on said shells engageable upon propulsion of the pinion member toward operative position to define said operative position of the pinion member.

2. An engine starter of the character described comprising: a pinion member including a threaded sleeve; a driving member having a threaded portion threaded into the pinion sleeve so that rotation of the driving member relative to the pinion member efiects propulsion of the pinion member toward an operative position at which it meshes with an engine gear; means for transmitting driving torque from a drive shaft to said driving member seas to effect relative rotation between said members comprising, a collar adapted to be fixed to the shaft, a shelllike housing encircling portions of the collar and MARY C..FITZ GERALD, I Erecutrz'x of the Estate of John W. Fitz Gerald,

Deceased. 

